2008 Mercedes SL-Class Owner's Manual - Page 111

Controls in detail Locking and unlocking To lock or unlock the vehicle, the SmartKey with KEYLESS-GO must be located outside the vehicle within approximately 3 ft (1 m) of a door or the trunk. If the vehicle has been parked for more than 72 hours, you must pull an outside door handle in order to activate the KEYLESS-GO function. In order to start the engine with the SmartKey with KEYLESS-GO: The SmartKey with KEYLESS-GO must be located in the vehicle. All doors must be closed. The brake pedal must be firmly depressed. Do not depress the accelerator. If you have started the engine with the KEYLESS-GO start/stop button ( page 41), you can only turn it off again with this button, even if you have put the SmartKey in the starter switch in the meantime. This does not apply if, after starting, the selector lever is still in position P and the SmartKey is then inserted in the starter switch. The SmartKey will then have priority over the KEYLESS-GO function and the vehicle's electrical system will operate according to the position of the SmartKey in the starter switch, even stopping the engine. If the SmartKey with KEYLESS-GO is positioned farther away from the vehicle, the system may no longer recognize the SmartKey with KEYLESS-GO. The vehicle then cannot be locked or the engine started via the KEYLESS-GO system. If the SmartKey with KEYLESS-GO is removed from the vehicle while the engine is running (e.g. if passenger exits the vehicle with the SmartKey with KEYLESS-GO), the message Key Not Detected will appear in the multifunction display while driving off. Find the SmartKey or change its present location immediately (e.g. place it on the passenger seat or insert it in shirt pocket). Remember that the engine can be started by anyone with a SmartKey with KEYLESS-GO that is left inside the vehicle. If you leave the SmartKey with KEYLESS-GO behind when exiting and locking the vehicle, the message Key Detected In Vehicle will appear in the multifunction display. 110